Excess molar volumes and excess molar enthalpies of the binary mixtures of 1,2-dichloropropane with di- and triethylene glycol mono-alkyl ethers at T = 298.15 K

The excess molar volumes VmE and excess molar enthalpies HmE at T = 298.15 K and atmospheric pressure for the binary systems of 1,2-dichloropropane (1,2-DCP) with di- and triethylene glycol mono-alkyl ethers have been determined by measuring density and heat flux, respectively. The density has been measured by using a digital vibrating-tube densimeter, whereas heat flux measurements have been carried out by using an isothermal calorimeter with a flow-mixing cell. The diethylene glycol mono-alkyl ethers are 2-(2-alkoxyethoxy)ethanols: diethylene glycol mono-propyl ether (DEGMPE), diethylene glycol mono-butyl ether (DEGMBE), and the triethylene glycol mono-alkyl ethers are 2-(2-(2-alkoxyethoxy)ethoxy)ethanols: triethylene glycol mono-methyl ether (TEGMME), triethylene glycol mono-ethyl ether (TEGMEE), and triethylene glycol mono-butyl ether(TEGMBE). It was found that both VmE and HmE values of the binary mixtures are negative over the whole composition range except for the mixture with very high mole fraction of 1,2-DCP(x1) in both DEGMPE and DEGMBE. In the case of 2-(2-(2-alkoxyethoxy)ethoxy)ethanols, the negative values of VmE and HmE continue to increase with an increase of the alkyl chain length of these alkoxyethanols. The minimum values of VmE shift from −0.1939 cm3 mol−1 for the mixture with DEGMPE to −0.40 cm3 mol−1 for the mixture with TEGMBE at x1 = 0.40–0.50. Also, the minimum negative values of HmE have been shown ranging from −472.9 J mol−1 (DEGMBE) to −800.5 J mol−1 (TEGMBE) at x1 = 0.40–0.50. The experimental results of both HmE and VmE were fitted to the Redlich–Kister equation. The experimental HmE data were also fitted to three local-composition models (Wilson, NRTL, and UNIQUAC). It was found that among these three models, the NRTL equation provides the most appropriate correlating result.